We are investigating about updating our UI. Clearly, I'm thinking about Premium Layouts. Although, I'd like to know how feasible it can be. I'm talking about a web apps, containing around 150 pages. We are using JSF templating, even though our web app structure is a bit messy, this should help us out to migrate into something fancier like Premium Layouts.

But, to convince our Team Leader, I have to ensure him that it's doable in a respectable time (let's say 3-4 months). This is why I'd like to receive some feedbacks among those who migrating from an existing app to Premium Layouts.